Metallic materials are widely used in various devices for electrochemical applications, including electrodes used in a chlor-alkali processes and separate/interconnect plates used in both low temperature (proton exchange membrane) and high temperature (solid oxide) fuel cells. Metal-based components are also used in batteries, electrolyzers, and electrochemical gas separation devices, for example. In these and similar applications, it is desirable for the metal-based components to have a surface with high electrical conductance (or low electrical resistance) to reduce the internal electrical losses that can occur in the electrochemical devices and achieve high operation efficiency in such devices. One of the difficulties usually encountered in electrochemical applications is that the metal-based component need also have high corrosion-resistant properties in addition to having high electrical conductance.
Coating metal-based components with a corrosion-resistant material, such as a chromium or nickel layer, for example, is a common industrial practice. These materials, however, cannot be used in some types of severe corrosive environments in electrochemical devices. While precious metals have excellent corrosion-resistant properties and are also highly conductive, they tend to be too costly for large-volume commercial applications.
Other materials, such as titanium, zirconium, and silicon, for example, can have outstanding corrosion-resistant properties, particularly after applying proper passivation treatments. These materials, however, have other limitations. For example, the electrical contact resistance of these materials is very high, especially after passivation. Moreover, these materials are too costly and/or are sometimes difficult to process. As a result, these materials can be limited in their commercial use.
Therefore, there is a need for technologies that can provide reduced-cost coatings for use in electrochemical applications that improve the electrical conductivity and/or corrosion-resistant of those substrates. Such coatings can be used in devices for electrochemical applications having metal-based components, such as fuel cells, batteries, electrolyzers, and gas separation devices, for example.